The present invention relates to a slide clamp for a disposable medical infusion cassette or tubing set, particularly to a safety slide clamp to prevent free-flow when the disposable cassette or tubing set is disconnected from a medical infusion administration device, and more particularly to a slide clamp having structure for cooperation with sensory apparatus on the infusion administration device for determining proper size and functional characteristics of the cassette or tubing set to which the slide clamp is secured.
Infusion of fluids, such as drugs and plasma, into a patient is desirable in the medical field. Two common infusion methods are intravenous delivery of fluids by gravity and either intravenous or in arterial delivery by mechanically pressurizing the fluids for delivery to the patient using infusion pumps. Modern infusion pumps typically administer mechanical forces to the exterior of a disposable device, such as a flexible plastic cassette or a flexible plastic tubing connected upstream to a medical fluid bag and downstream to the patient.
In a cassette type infusion pump, disposable cassettes have been advantageously employed for providing a simple disposable element in combination with a relatively straightforward pumping action. The cassette for this type of pump typically has one or more interconnected pumping chambers, and input and output tubing. The cassette and tubing are placed into contact with the pump or a pumping mechanism so that the contents or medicinal fluid pumped through the cassette and tubing are maintained in a sterile condition.
In another type of infusion pump, the pumping mechanism engages directly onto the tubing acting thereon with sequential compression forces to move the fluid through the tubing to the patient. This is called a peristaltic pump. Once again, the tubing set connected to the desired supply of medicine is inserted into the pumping mechanism maintaining a sterile condition of the medicinal fluid. Maintenance of a sterile condition is facilitated by disposing of the medicinal tubing set and simply replacing it with a newly sterilized and filled set as additional quantities of fluid are to be infused or when a new medicine is provided to a new patient.
Thus, disposable infusion tubing sets and disposable cassette sets are currently the standard of the industry for infusion flow control, whether through cassette pumps or through peristaltic pumps. One prior cassette pump and safety flow clip was designed for receiving the safety flow clip attached to the output tubing of a disposable cassette. Such a device is disclosed in U.S. Pat. No. 5,437,635, inventors Fields, et al., issued Aug. 1, 1995. The flow clip was designed to permit the operator to stop flow of fluids through the disposable cassette whether it was in or out of the pump. Also the receiving mechanism and flow clip were designed such that the cassette or the tubing set could not be installed unless the safety flow clip was in place. Flow was automatically closed if the cassette was not held in the proper operable pumping position. The cassette could not be removed until the flow clip was closed. Still the safety clip on the cassette could be manually moved from closed to open flow when the cassette was removed from the pump. The cassette set was also installable into the pump whether the safety clip was closed or open.
Of concern with respect to medical infusion pumps, whether cassette pumps or peristaltic pumps, is that the pumping capability and the accuracy of the pumps can depend in large part upon the size and functional characteristics of the cassette or tubing set. The functional characteristics can be affected by thickness, type of material, volume, resilience or any number of other features of the cassette or the tubing set. Thus, the use of one pumping cassette or one tubing set having particular size and functional characteristics can be properly calibrated for accurate, safe and controlled pumping and the use of another set with different size or different functional characteristics can be improper, inaccurate and possibly dangerous to the patient, unless the pumping parameters are appropriately adjusted to the different size and functional characteristics. Currently there is no known device or system that might automatically prevent such mismatching. The industry is currently relying on the ability of operators to distinguish size and on labeling and the competency of the operators to avoid this potentiality.
Thus, what has been invented is a slide clamp device for use on disposable medical infusion sets used with a medical infusion pump designed for operation with a flexible flow tube of the infusion set, having predetermined size and functional characteristic. The slide clamp device comprises a slide clamp body and a tube carrier. The tube carrier is insertable over the slide clamp body and the medical flow tube is secured to the tube carrier. The flow tube is either fastened to a cassette or integrally formed with the tubing set having predetermined size and function characteristic. The tubing is thus secured through the slide clamp to the tubing carrier so that neither can be removed from its engagement with the preselected infusion set having predetermined size and function characteristics whether the tubing set or the cassette set. The slide clamp comprises a grasping end attached to an opaque clamp plate. The clamp plate extends longitudinally from the grasping end. The clamp plate defines a clamp slot with a wide-open portion sized for receiving the flow tube without closing the tube, a narrow open portion sized for closing the flow tube and a transition portion interconnecting the wide and narrow portions such that movement of the clamp body relative to the tube moves the tube through the transition from open to closed or from closed to open depending upon the direction of relative movement. Further, according to the invention, a plurality of orifices are formed along the longitudinal clamp plate at predetermined positions arranged according to the size and functional characteristics of the tubing or cassette. The pump is provided with an engagement mechanism for the slide clamp having sensors for detecting the existence or absence of orifices at the predetermined locations. In the case of the plurality of the orifices, miniature light emitters are mounted at one inside wall of the engaging mechanism and adjacent receptors are mounted at the opposite inside wall of the engaging mechanism so that with the flow clip properly engaged in the receptacle, the existence of orifices at particular ones of the plurality of predetermined locations is sensed. The sensor data is communicated to pump control circuitry to allow the pump to operate according to the predetermined size and functional characteristics indicated by the location of the plurality of orifices.
In an alternative embodiment the pump may be designed with the capability for changing programming for pumping operation, so that a plurality of separate sets of cassettes or flow tubing, each having different size or functional characteristic may be properly operated by the same pump. A flow clip for each of the preselected different variations of size and/or functions of tubing sets or pumping cassettes for which the pump is programmed would have orifices through the opaque flow clip plate at different orientations or different locations. Upon insertion of the flow clip assembly into the receptacle, a plurality of sensors, arranged at a plurality of positions in the walls of the receptacle will sense the different orientations or different combinations of orifice positions in the flow clip and it will be identified electronically by pump control circuitry. The pump control circuitry activates separate sets of control parameters depending upon the locations of the orifices through the flow clip inserted into the receptacle. Thus, with the invention of a flow clip with a plurality of detectable orifices one pump can be preprogrammed to operate only with identified flow clips signifying proper size and function or characteristics and also to operate differently for different identified tubing sets or different identified cassettes.